r eaton



Patented Oct. 6, 1925.

UNITED STATESv l 1,555,838 PATENT OFFICE.

GEORGE It.' EATON, or OAK PARK, ILLINOIS, AssIeNoa rifo KELLOGG swI'ioHBoAnn ANL SUPPLY COMPANY, OP' CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Application filed February 19, 1921. Serial No. 446,241.

To all whom t may concern.'

Be it known that I, GEORGE R. EATON, a citizen of the United States of America, anda resident of Oak Park, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Telephone Systems, of which the following is a speciication.

My invention relates to telephone systems and has to do more particularly with a reverting busy test, by which the operator receives a distinctive busy signal when a test is being made at a jack multiply con.- nected with a jack in which the answering plug has been inserted, and an object of my invention is the provision of an improved and simplified circuit arrangement which is positive in its operation.

My invention is illustrated in connection with an operatoijs cord circuit which is arranged for automatically cutting in the operators telephone set on the cord conductors when an answering plug is inserted into a jack of the calling line and for automatically disconnecting` said operators telephone set from the cord conductors when the connection is completed by the insertion of a calling plug into the multiple jack of a called line.

My invention is also applicable for use in connection with cord circuits whichv are arranged for manually connecting the operators telephoneset with the cord conduc tors by the actuation of a listening key, and it is to be understood that I do not wish to be limited to the specific circuit arrangement as shown, as I intend using the test circuit of my invention in connection with other cord circuits.

For a more complete understanding of my invention, reference may be had to the accompanying drawings, in which Fig. l illustrates the reverting busy test circuit of my invention used in connection with a two-conductor cord circuit provided with automatic listening; and

Fig. Q illustrates the reverting test circuit of my invention used in connection with a three-conductor cord circuit provided with automatic listening.

Referring now more in detail to Fig. l, I show a party-line PL which has connected to it substations A and B. The line terminates at the exchange in a line circuit L i comprising a line relay LR, cut-oft' relay CO,

line signal S and the multiple jacks J and '7'. The cord circuit C comprises an answeringy plug APand a calling plug CP, the two cords being connected by the heavily marked talking conductors kwith condensers K and K interposed. The answering end of the` cord circuit has an answering tip supervisory relay AT and 'an answering sleeve supervisory relay AS, the two relaysr controlling answering supervisory lamp AL. The answering sleeve supervisory relay AS energizes when the answering plug AP is inserted into a jack J of the calling line to connect the operators set O to the cord conductors. `The calling end of the cord circuit C has a calling tip supervisory relay CT and a calling sleeve supervisory relay CS, the two relays CT and CS controlling calling supervisory lamp CL. The callingr sleeve supervisory relay CS actuates when the calling plug CP is inserted into the jack J of the wanted line, and upon energization automaticallydisconnects the Operators set O from the cord conductors. A ringing key RK is also provided, which when actuated connects the ringing generator G for signaling the calledv substation.

To the right of the drawing I illustrate substation D, similar to that illustrated at substations A and B, said substation D being connected at the exchange in a line circuit L similar tothe line circuit L. The reverting tone' test circuit TTv comprises a polarized relay PR which is common to an operators position and comprises a high resistance winding H and a low resistance winding LO and an armature AM. The winding I-I is energized whenever an operator tests the multiple jack of a busy line and attracts the armature AM to close a contact 4in the circuit of the low resistance winding LO through its alternate contact. The

low resistance winding LO is operatively effective only when a multiple jack of the same calling line is tested. The coils II and LO of the polarized relay PR are woundso as to oppose each other for purposes as will be more fully hereinafter described.

When a party calls for another party on the ,same line and the operator tests yin the usual manner by placing ythe tip of the calling plug to the sleeve of themultiple jack of the wantedline, the winding H of the polarized relay PR is energized and attracts its armature AM, ,which closes its Contact to energize the low winding LO, which closes a shunt about the winding H, and conseqently the armature AM retracts and opens the circuit of the winding LO.

lVhen` the polarizedv relay PR is in this conf dition an energizing circuit is again established tor the winding H, which attracts the armature AM and again closes a circuit for the winding LO, and the winding LG in turn places va shunt about the winding H. Due to this a vibratory circuit is established through the windings H and LO, and the vibration of the armature AM produces a regular vibratory tone which is transmitted to the operators head receiver, notifying her that the called substation that is wanted is on the saine line as that of the calling subscriber. lVhen a busy line other than the calling line is tested, although the winding H is energized to close a circuit through the winding LO, the winding LO is not effective to. shunt H and the operator receives the usual busy click only, notifying her` ot the busy condition of the line, all of which will be inore fully hereinafter described.

Assuming now that a subscriber at the substation A vishes to converse with another subscriber,r say at the substation B on the saine party line, the subscriber at A removes his receiver from the switchhook, causing the energization of the line relay LR. It attracts its armature to light the line signal S. The operator, in response inserts an answering plug AP into the jack J, closing an energizing circuit including` the answering sleeve supervisory relay AS ot the cord circuit C and the cut-oitrelay CO of the line circuit, from battery through the winding of AS, `sleeve contact ot the connected plug AP and j ack J, to ground through the winding` of the cut-oit relay CO. TheV latter operates and opens the circuit of' LR, which de-energizes and ett'aces line signal S. The answering` tip supervisory relay AT ot' the cord circuit C also'operates troin'ground through the relay AT, tip contacts of the plug AP and jack J, through the substation A and back through the sleeve contacts of the jack and plug and through the winding ot" relay AS to battery. The relay AT upon energizing opens its norma-l contact 50 tov prevent the answering supervisory signal AL from lighting. The closing of alternate contacts 10 and 11 of the answering sleeve supervisory relay AS connects the operators telephone set OV to the cord conductors, and the operator now inquires the want of the calling subscriber. Having received the number` she tests the multiple jack ot' the called line to determine its idle or busy condition. perhaps not knowing that the called subscriber B is located on the same party line with the calling subscriber A. In testing she places the tip of the calling plug CP against the sleeve ot' the multiple jack j ot` the Wanted substation B in the usual inanner. The sleeve of the jack J is at a battery potential above ground and a circuit extends froml battery through the wind-ing ot' the answering sleeve supervisory relay y through the sleeve contacts of the connected plug AP and jack J, over conductor 12 to the sleeve contact 13 of the multiple jack j of the called line B. lhen the tip of the plug fl is placed against this sleeve 13, an energizing circuit is established for the high resistance winding H ot the polarized relay PR ot the test circuit TT, traced troni batteryat the sleeve 13 ot the jack j, through tip Contact 141; ot the calling plug CP, noiinal contact 15 ot' the ringing key RK, norlnal contact 16 otthe calling sleeve supervisory relay CS, conductor 17, to ground through the Winding H ot the polarized relay PR. The winding H, upon energization. attracts the armature AM ot the polarized relay against the spring tension ot' the coil spring 1t 2 suitably fastened to the armature AM to close the contact 18 ot said relay PR, and the closure of this contact establishes an energizing circuit tor the low resistance winding LO of the polarized relay '3l-. traced 'troni ground through said low resistance winding, alternate contact 18, ariuature Alti. conductors 19 and 20, contact 11, conductor 21, contact 22, conductor 23, through the winding of the relay AS to battery and ground` The circuit just traced through the low resistance winding L@ shunts the winding H when the tip 14 ot the plug CP touches the sleeve 13 of the multiple jack j ot the wanted line, because both winding H and Winding L@ are then conductively connected to the winding ot relay AS and so to battery. As the windings H and L() are wound to oppose each other, the winding L() upon energization tends to repel the armature Ali/I which was attracted upon the energization ot winding H. The shunt circuit about the winding H, as already described. decreases the current tlow through the said winding H and the opposed winding LO overcomes the attractive force ot the winding H, and due to the attract-ive 'torce ot the winding LO and the pulling effect of the spring 182 the armature AM retractsV to open the alternate contact 18. A stop 192 is provided on the relay PR tor limiting' the pivotal movement ot the armature AM when the armature is moved to open contact 18. The opening ot alternate contact 18 interrupts the energizing circuit through the low winding LO, and upon the opening oit alternate contact 18 ot' the rela-y PR the shunt is removed troni about the winding H and the winding H again attracts the armature AM, and upon the closure of alternate contact 18 an energizing circuit through the low-wound winding LO is again closed. As long as the tip ot' the plug C? remains in contact With the sleeve orn the jack J a vibratory circuit for the windings H and L@ of the polarized relay Yi?, thus exists, causing the armature AM to if'ibrate, which produces a special buzzing tone transinitted to the operators head receiver, indicating' to her that she has tested a multiple jack of the calling line. The special tone inay be traced troin potential at the vibrating armature AM, over conductors '1.9 and 2O through the operators head receiver to ground through AT, and this tone is also 'transmitted to the calling subscriber troni the vibrating arinature over conductors 19 and 20, alternate contact ll ot relay conductor 21, nornial contact 22, conuetor sleeve contacts oit the jack d' and i .A l) and through the receiver at the st tion A and back to ground through winding of relay AT. 'lhe operator then notiity the calling subscriber at the, s station A to replace his receiver upon i sivitchhook so that she inay ring the leu-tor subscriber B, and she Will then :he calling plug CP into the jack of line, ,vhich in this case would be the She then reinoves answering plug he relay CS is energized, closing the circuit 'for the calling supervisory lainp CL. The operator Will then signal the called-tor subscriber on the party line by actuating the rin;l hey RK to connect ringing genertor il, to operate the bell at the called subfiaiion. Upon both subscribers removing their receivers, they are ready for conversation. Upon replacing their `receivers the usual disconnect signal is given and the operator withdraws the plug.

Assuming nonv that the subscriber at the substation A Wishes to converse With a subscriber at the substation D, the operation of this circuit is the saine as previously described. and relay C() of the line circuit L and the relays AT and AS of the cord circuit C operate as before described. The

operatoi"s telephone set O is automatically connected to the cord conductors so that the operator may ascertain the Want of the calling subscriber at the substation A, and having uned that it is the substation D that is Wanted, the operator noiv tests the inule tiplo` jack J of the called line as to its idle busy condition. lt the line is busy there will be a battery potential upon the sleeve or"y the multiple jack l from another cord circuit connected thereto, aid assuming that the line is busy, the placing of the tip of the ,4 kI to ground, through the Winding or high resistance Winding H, and the said winding H upon cnergization attracts the lug Cl? against the sleeve of the jack J ofk armature AM. rlhe closing of alternate contact 18 ot the relay PR, upon the attraction of the armature AM, closes an energizing circuit for the loiv resistance Winding L@ ot the polarized relay PR, troni ground through the Winding Il@ to battery and4 ground, through the answering sleeve supervisory relay AS, over the path previously described. rlhus, the Winding H of the polarized relay PR energizes Wienever a busy line is tested, and the Winding LO is also energized When a busy line is tested, but there is no shunt placed about the Winding` H ot the relay PR when the operator tests the multiple Ajack'il of a called line, which is a line other than a calling line, because in the present instance, although Winding LO gets its current through relayy AS of own cord as before, `he relay H now gets its current through a relay AS (or CS, as the case inay be) of soine other cord circuit than the one to which it belongs. The windings ll and L@ oppose each other as betore, but the Winding El holds the armature Ani attracted in this case because it is not shunted as just explained. Each tiine the operator tests jack J she gets al single eliclr tet if the line is busy, and no click it it is lCl .(5.

lr idle, the operator insert the calling plug CP into the multiple jack J, closing an energizing circuit of the calling sleeve supervisorj.' relay C@ and the cut-oit relay C ot the line circuit L. The relay QS opens its normal contacts Q2 and 5i, disconnecting the operators set 'O troni the cord conductors. The opening of normal Contact lo of the relay CS cuts off Winding E, and the closing or its alternate Contactk 52. foin# pletes the continuity of the tip conductor ot the cord, The operator then actuates the ringing lrey RK, connecting` ringin K to the tip side ot the line to ring the calledfor subscriber. .The ringing current eircuit being traced as follows:y troni ground through the generator G, al' Contact l5 ot the ringing key RK, tip conta:y ts oi the plug CP and jack J', upper alternate contact oi the cut oit relay CO', through the call bell at the substation D, the lower alten nate contact oi` relay CO', slee 'e contacts ot the jack J and plug Cl?, alternate contact l5 of ringing key RK, through the resistance i t0 ground at g. The calling supervisory signal CL is lighted through alternate contact 52 to ground and remains in its generator (i zation ot the answering` tip supervisory relay AT and the calling' tip supervisory relay CT to close circuits Jfor lamp AL and lainp CL. The operator now withdraws the answering plug AP and the calling plug Ul 'lroin their respective jacks J and J, which brings about the de-energization ot the relays C() and CG and of relays AS and CS oitl the cord circuit, which brings about the etlaceinent ot the supervisory signals AL and CL.

Referring now to Fig. 9 l illustrate iny invention adapted tor use in connection with a three-wire cord circuit, and to the 'lett oit' the drawing l show a party line comprising subscribers A and B, the said party line terrninating at the exchange in a line circuit L2, comprising the usual cut-ofi" relay Coi line relay LRQ, supervisory signal S2, inultiple jacks J2 and j. rllhe three-wire cord circuit C comprises an answering plug` AP and a calling plug` CP, the two plugs being connected by the heavily lnarlred talking conductors. The answering end et the cord circuit C comprises an answering sleeve rclay AS and a supervisory relay Sli, the two relays controlling the answering supervisory lainp AL. rlhe calling end ot the cord circuit C comprises the calling sleeve relay CS and the supervisory relay SR, the two relays controlling` the calling supervisory signal CL. A ringing key lili is also shown, which when actuated connects the ringing generator G ot the called line to transmit ringing current to actuate the call bell thereat.V The answering sleeve relay AS is energized when the answering plug AP is inserted into the jack of the calling line to connect the operatorsset O to the cord conductors, and the calling sleeve relay CS energizes when the calling plug CP is inserte into the ack of the called line, which relay CS upon energization auto- `inatically disconnects the operator-s set O troni the cord conductors.

To the right ot the drawing` l illustrate a siistation D similar to that illustrated at the substations A and B, the said substation D terminating at the exchange in a line circuit Ls siinilar to L2` said line circuit L2 comprising line relay LRS, cut-ott relay Cllr, line signal S3 and the multiple acls J3.

The revertive tone test apparatus TT associated with the cord circuit C comprises a polarized relay PR. having a high winding H and a low winding LQ and an arniature AH. and the operation ot the test circuit Trl" associated with the three-wire cord circuit as illustrated in this ligure is siniilar to that ot the revertive test circuit 'l as illustrated in connection with l? l. 1

Assuming that the subscriljier A initiates a call, the rcn'ioval of, the receiver brings about the enere'ization ot the line relay LB: to light the une signal S2. The

operator inserts an answering plug AP into the jack J2 of the calling line, bringing about an energization ot the cut-ott relay C02 and the answering sleeve relay AS, and also bringing about the energization of the supervisory relay SR, which relay upon energization prevents the lighting of the answering supervisory lainp AL at this ti ne. The closing ot' alternate contacts GO, Gl and G2 of the relay AS connects the operators set G to the cord conductors, and the operator now inquires the want ot the calling subscriber. Having received the number ot the called subscriber, she tests a multiple jack ot the called line to deterinine its idle or busy condition. Assuming that it is the subscriber B ot the sanie party line that is wanted, the operator tests the multiple jack of the wanted line by placing the tip ot' the calling plug CP against the sleeve of the jack. rllhe sleeve ot' the jack y" being at a battery potential above ground, which extends from battery through the winding ot the answering sleeve relay S, through the sleeve contacts of the connected plug AP and jack 52, over conductors 63 to the sleeve of the multiple jack j of the line that is now being tested. TWhen the tip ot the plug CP is placed against the sleeve of the jack j an energizing circuit is established for the high resistance winding H of the polarized relay PR ot the test circuit TT, over a path traced troni battery at the sleeve 6a ot the acl: y" through the tip G5 of the calling plug the normal contact GG of the ringing key Rll, conductor G7, through alternate Contact Gl of the answering sleeve relay S, the conductor 67, norinal contact GS ot the sleeve relay CS, conductors 69 and T0, to ground through the high winding ll of the polarized relay PR. The winding H upon energization attracts the arinature All against the tension ot the coil spring 183 fastened to armature AM to close its alternate contact 18, and the closure of this contact 18 establishes an energizing circuit tor the low resistance winding LO ot' the polarized relay PR, traced troni ground through the winding of the said relay L, alternate contact 18, the arinature Alil, conductor Tl, norinal contact 72 ot the relay CS, conductors 7S, through alternate contact GO of the answerki sleeve relay S, to battery and ground :ough the winding ot the said relay AS. stop l93 is provided for limiting the pivotal niovenient of armature Ahi in one direction.

The circuit just traced through the low resistance winding LQ shunts the battery tlow that liows through the winding H when the tip o3 of' the plug CP touches the sleeve (il ot the multiple aclr y" ot the wanted line, and the operation ot the tone test circuit TT Cil of l? ig. 2 is the same as described in connection with Fig. l and transmits kafrevertive buzzing vtone to the head receiver in the operators set O', notifying her that she has tested a. multiple jack which is connected with the jack in which the answering ,plug All is inserted. rlhe operator on receiving this revertive tone notifies the calling subscriber at the substation A to replace his receiver upon its suitchhook so that she may ring the called-for substation l. The operator will then insert the calling plug CP into the jack J2 of the said line, and the opening of normal contacts 72, G8 and disconnects the operators s et O from the cord conductors, and the subscriber at the substation B Will be signaled in the usual manner by the actuation of the ringing key Eli, the operator having first removed answering plug AP. The resistance RE associated with the operators set 0 is placed in circuit during Athe time that the operatorls set is connected to the cord conductors, through alternate contact of the relay AS" and the normal contact 'lor' the relay CS', to balance the operator"s circuit when the Winding H is connected. thereto, as already described. Upon the response ot the subscriber the substaticns ik and B are ready for conversation, and upon replacing their receivers the usual disconnect signal is given and the operator withdraws the plugs.

ilvhen the operator tests the multiple jack of a called line other than the one in which the answering plug has been inserted, the operation of the tone ktest TT is the same as described in connection with Fig. l, and the operator receives the usual click in Aher head receiver, notifying her of the busy condition of the Wanted line, anda further description of the tone test circuit TT is not thought necessary.

lWhile l have illustrated my invention operating in connection with a specific circuit arrangement, l do not wish to be limited to the same, as the revertive tone test of my invention is adapted -for use in connection with other circuit arrangements and changes and modications may readily suggest themselves, but l aim to Coverall such changes and modifications as come Within the spirit and scope of the appended claims.

What I claim as neW and desire to secure by Letters Patent, is: i

l. A telephone system including a calling line and a link circuit connected thereto at one end, and having at the other end a test terminal adapted to be applied to said line to test it, and reverting test means including a high resistance relay Winding energized on such application, a low resistance relay Winding cut in responsive to such energization, to shunt and oppose said high Winding, to produce a' characteristic busy tone.

2. A telephone system including. a calling yline and a link circuit connected by its one end tosaid line, and having at Lits other end a terminal adapted'to be applied directly to a limb of said `line to test it, and test means including reverting test apparatus having a polarizedy relay for said circuit, said polarized relay having one of its Windings energized when any busy line is tested to operate an armature contact a single stroke, and another relay Winding opposing saidfirst Winding effectively operated on a revertive test only to cause a vibratory movement of' said armature contact.

A telephone system including a calling line and a link circuit connected thereto at its rone end, a terminal at the other end of the circuit having test means including reverting test apparatus comprising a polarized relay with an eiiicient Winding energized when a busy line is tested,va relavtively inefficient Winding roi' said relay cut in by energization of the first Winding, and

4shunting means for said second Winding to render said second Winding inefficient on a reverting test only. y

4f. A telephone system including telephone lines and a link circuit for interconnecting them` having a yterminal adapted to be applied to said lines to test them,a polarized relay for said terminal having a Winding energized by current over said terminal Wherever a test of a busyline is made, an opposing Winding for said relay energized by a contact closed responsive to the energization of the first Winding, said opposing 1vinding ineffective to overcome the initial energization of the first winding, and means including said opposing Winding to drain current from the lirst Winding on a reverting test only.

5. ln a multiple switchboard, a link circuit,`an operators telephone set for said link circuit, automatic means for connecting and disconnectingy saidr operators telephone set and said link circuit, reverting test apparatus including a link circuit polarized relay energized directly by current rom the test terminalk of the circuit, to operate its armature a single stroke on each non-reverting test of a busy line, and means including va shunt about said relay for causing it to operate its armature a plurality of strokes at each test on areverting call, said shunt including a Winding of `one of the magnets of said relay.

6. In a telephone system, a party line 'and an operators cord circuit having its answering plug connected to a jack of said line, a test relay having an energizing Winding in circuit with the calling plug when used as a test plug, a circuit for energizing said Winding on a reverting call, said circuit including a contact of the answering plug, and a short circuit about said ansWer` ing plug contact closed by the energization .of said winding to shunt and oppose said winding to render the same ineffective.

7. A telephone system comprising a telephone line, multiple jacks therefor, a link circuit provided with a revertive tone test relay having opposing windings and having its answering terminal connected to a multiple jack of said line, a circuit for energizing said tone test relay when the calling terminal of said circuit is applied to another multiple jack of said line, said circuit including a contact of the answering terminal and a switch contact operated by said relay to short-circuit said contact of said answering terminal.

8. A telephone system comprising telephone lines, multiple terminals therefor, a link circuit provided with a polarized revertive tone test relay having its answering terminal connected to one of said multiple terminals, means for energizing a winding of said relay when the calling terminal of said circuit is applied to the multiple terminal of any busy line, a contact closed on enereization of said winding to cut in another winding of said relay opposing said first winding, and a connection thereon effective to shunt said first winding effective only when said calling terminal tests the line connected to said answering terminal.

9. A telephone system including telephone lines having multiple terminals, a link circuit for interconnecting said lines, a polarized revertive tone test relay, means for energizing the two windings of said relay in opposition when any busy line is tested, and means for energizing both of said windings in opposition and shunting one of them when the answering terminal of said link circuit is connected to one of said lines and the calling terminal of said circuit is 'used to test said line.

10. A telephone system including telephone lines having multiple terminals, a link circuit for interconnecting said lines having its answering terminal connected to one of them, an operators telephone set, means responsive to the connection of the answering and calling terminals'of said link circuit to said lines as calling and called lines to automatically connect and disconnect said operators telephone set and said link circuit, a polarized test relay for Athe calling terminal having two windings, an armature contact for said relay connected to a test receiving instrument, means for producing a steady energization of the windings of said relay when another and busy line is tested, and a circuit for the windings of said relay for producing a vibratory energization of said relay on a revertive test to give an indication to the operator, said circuit including a shunt about one of said windings of said relay.

11. A telephone system including telephone lines having multiple terminals, a polarized test relay having windings opposing each other when testing, circuit conditionseflective on one condition of testing a busy line to cause one winding to prevail, and circuit conditions effective on another condition of testing a busy line to cause the other winding to prevail, said last condition including a shunt about the first winding.

12. A telephone system including telephone lines having multiple terminals, a link circuit connected at one end to a terminal of a calling line, a polarized test relay having one winding connected to the testing conductor of said cord circuit and having an armature Contact actuated by said winding on testing another and busy line to connect its other winding to another conductor of said circuit, said windings being then in opposition and said first winding prevailing, a test receiving instrument sensitive to actuation of said relay, .and test circuit connections conductively uniting said first winding to said other conductor only when a revertive test is made.

13. A telephone system comprising a calling telephone line, multiple jacks therefor, a cord circuit having Van answering terminal and a calling terminal, an operators telephone set, means for connecting said operators telephone to said cord when said answering terminal is inserted into one of' said jacks, a polarized relay having a high resistance coil and a low resistance coil, an armature for said relay connected to said operators telephone set, circuits for said coils Vfor operating the same to produce a single movement of said armature, and circuits for operating said coils to cause a vibratory movement of' said armature.

Signed by me at Chicago, in the county of Cook and State of Illinois, this 17 day of February, 1921.

GEORGE R. EATON. 

